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Mirrors > Home > MPE Home > Th. List > cmpfii | Structured version Visualization version GIF version |
Description: In a compact topology, a system of closed sets with nonempty finite intersections has a nonempty intersection. (Contributed by Stefan O'Rear, 22-Feb-2015.) |
Ref | Expression |
---|---|
cmpfii | ⊢ ((𝐽 ∈ Comp ∧ 𝑋 ⊆ (Clsd‘𝐽) ∧ ¬ ∅ ∈ (fi‘𝑋)) → ∩ 𝑋 ≠ ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fvex 6859 | . . . . 5 ⊢ (Clsd‘𝐽) ∈ V | |
2 | 1 | elpw2 5306 | . . . 4 ⊢ (𝑋 ∈ 𝒫 (Clsd‘𝐽) ↔ 𝑋 ⊆ (Clsd‘𝐽)) |
3 | 2 | biimpri 227 | . . 3 ⊢ (𝑋 ⊆ (Clsd‘𝐽) → 𝑋 ∈ 𝒫 (Clsd‘𝐽)) |
4 | cmptop 22769 | . . . . 5 ⊢ (𝐽 ∈ Comp → 𝐽 ∈ Top) | |
5 | cmpfi 22782 | . . . . 5 ⊢ (𝐽 ∈ Top → (𝐽 ∈ Comp ↔ ∀𝑥 ∈ 𝒫 (Clsd‘𝐽)(¬ ∅ ∈ (fi‘𝑥) → ∩ 𝑥 ≠ ∅))) | |
6 | 4, 5 | syl 17 | . . . 4 ⊢ (𝐽 ∈ Comp → (𝐽 ∈ Comp ↔ ∀𝑥 ∈ 𝒫 (Clsd‘𝐽)(¬ ∅ ∈ (fi‘𝑥) → ∩ 𝑥 ≠ ∅))) |
7 | 6 | ibi 267 | . . 3 ⊢ (𝐽 ∈ Comp → ∀𝑥 ∈ 𝒫 (Clsd‘𝐽)(¬ ∅ ∈ (fi‘𝑥) → ∩ 𝑥 ≠ ∅)) |
8 | fveq2 6846 | . . . . . . 7 ⊢ (𝑥 = 𝑋 → (fi‘𝑥) = (fi‘𝑋)) | |
9 | 8 | eleq2d 2820 | . . . . . 6 ⊢ (𝑥 = 𝑋 → (∅ ∈ (fi‘𝑥) ↔ ∅ ∈ (fi‘𝑋))) |
10 | 9 | notbid 318 | . . . . 5 ⊢ (𝑥 = 𝑋 → (¬ ∅ ∈ (fi‘𝑥) ↔ ¬ ∅ ∈ (fi‘𝑋))) |
11 | inteq 4914 | . . . . . 6 ⊢ (𝑥 = 𝑋 → ∩ 𝑥 = ∩ 𝑋) | |
12 | 11 | neeq1d 3000 | . . . . 5 ⊢ (𝑥 = 𝑋 → (∩ 𝑥 ≠ ∅ ↔ ∩ 𝑋 ≠ ∅)) |
13 | 10, 12 | imbi12d 345 | . . . 4 ⊢ (𝑥 = 𝑋 → ((¬ ∅ ∈ (fi‘𝑥) → ∩ 𝑥 ≠ ∅) ↔ (¬ ∅ ∈ (fi‘𝑋) → ∩ 𝑋 ≠ ∅))) |
14 | 13 | rspcva 3581 | . . 3 ⊢ ((𝑋 ∈ 𝒫 (Clsd‘𝐽) ∧ ∀𝑥 ∈ 𝒫 (Clsd‘𝐽)(¬ ∅ ∈ (fi‘𝑥) → ∩ 𝑥 ≠ ∅)) → (¬ ∅ ∈ (fi‘𝑋) → ∩ 𝑋 ≠ ∅)) |
15 | 3, 7, 14 | syl2anr 598 | . 2 ⊢ ((𝐽 ∈ Comp ∧ 𝑋 ⊆ (Clsd‘𝐽)) → (¬ ∅ ∈ (fi‘𝑋) → ∩ 𝑋 ≠ ∅)) |
16 | 15 | 3impia 1118 | 1 ⊢ ((𝐽 ∈ Comp ∧ 𝑋 ⊆ (Clsd‘𝐽) ∧ ¬ ∅ ∈ (fi‘𝑋)) → ∩ 𝑋 ≠ ∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 ∧ w3a 1088 = wceq 1542 ∈ wcel 2107 ≠ wne 2940 ∀wral 3061 ⊆ wss 3914 ∅c0 4286 𝒫 cpw 4564 ∩ cint 4911 ‘cfv 6500 ficfi 9354 Topctop 22265 Clsdccld 22390 Compccmp 22760 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-10 2138 ax-11 2155 ax-12 2172 ax-ext 2704 ax-sep 5260 ax-nul 5267 ax-pow 5324 ax-pr 5388 ax-un 7676 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-3or 1089 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1783 df-nf 1787 df-sb 2069 df-mo 2535 df-eu 2564 df-clab 2711 df-cleq 2725 df-clel 2811 df-nfc 2886 df-ne 2941 df-ral 3062 df-rex 3071 df-reu 3353 df-rab 3407 df-v 3449 df-sbc 3744 df-csb 3860 df-dif 3917 df-un 3919 df-in 3921 df-ss 3931 df-pss 3933 df-nul 4287 df-if 4491 df-pw 4566 df-sn 4591 df-pr 4593 df-op 4597 df-uni 4870 df-int 4912 df-iun 4960 df-iin 4961 df-br 5110 df-opab 5172 df-mpt 5193 df-tr 5227 df-id 5535 df-eprel 5541 df-po 5549 df-so 5550 df-fr 5592 df-we 5594 df-xp 5643 df-rel 5644 df-cnv 5645 df-co 5646 df-dm 5647 df-rn 5648 df-res 5649 df-ima 5650 df-ord 6324 df-on 6325 df-lim 6326 df-suc 6327 df-iota 6452 df-fun 6502 df-fn 6503 df-f 6504 df-f1 6505 df-fo 6506 df-f1o 6507 df-fv 6508 df-om 7807 df-1o 8416 df-en 8890 df-fin 8893 df-fi 9355 df-top 22266 df-cld 22393 df-cmp 22761 |
This theorem is referenced by: fclscmpi 23403 cmpfiiin 41067 |
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